1. Technical Field
The present disclosure relates to a wireless power transmission apparatus and a wireless power transfer system which transmit power in a non-contact manner through magnetic coupling between a power transmission coil and a power reception coil.
2. Description of the Related Art
Recently, various types of mobile equipment including a cellular phone have become popular. The amount of power consumption of the mobile equipment has been increasing due to improvement in the functions and the performance of the mobile equipment and due to increased variety of content. An increase in the amount of power consumption of mobile equipment that operates with a battery having a predetermined capacitance causes the operation time of the mobile equipment to be shortened. As a technology for compensating the limitation on the capacitance of a battery, a wireless power transfer system is receiving attention. The wireless power transfer system transmits power in a non-contact manner from a wireless power transmission apparatus to a wireless power reception apparatus through electromagnetic induction between a power transmission coil of the wireless power transmission apparatus and a power reception coil of the wireless power reception apparatus. In particular, a wireless power transfer system using a power transmission coil and a power reception coil of resonance type (coupling of a resonant magnetic field) is capable of maintaining high transfer efficiency even when the position of the power transmission coil is misaligned with that of the power reception coil. Therefore, applications of this technology in various fields are expected.
For example, wireless power transfer systems disclosed in Japanese Unexamined Patent Application Publication No. 2010-016985 (PTL 1), International Publication No. 2012/081519 (PTL 2), International Publication No. 2012/164744 (PTL 3), and Japanese Unexamined Patent Application Publication No. 2013-034367 (PTL 4) are known. According to the wireless power transfer systems in PTL 1 to PTL 4, two coils are coupled through a high-frequency magnetic field which occurs in a space near the coils, whereby power is transmitted in a non-contact (wireless) manner through the space between the coils.
However, in the related art, simultaneous power supply from a wireless power transmission apparatus to multiple wireless power reception apparatuses fails to be adequately performed in a non-contact manner.